The background of this invention resides in the field of telegraphy and data transmission. Heretofore, data transmission over wire facilities to a load such as a teleprinter or the like, at remote distances was accomplished by conventional voltage sources applied to the load by employing relays or solid state switches or equivalent devices.
Larger systems requiring many teleprinters at varying distances required an individual adjustment for each printer in order to achieve the prescribed current driving level for the given printer. The present invention on the other hand permits the prescribed current level to be adjusted one sole time for any distance in the magnitude of several kilometers.
In former systems, the high voltage supply powering the system had to be of high quality and constant output thereby expensive to a high degree. Otherwise, large fluctuations in the voltage, proportionately causing the current to the load to fluctuate, resulted in increased distortion and data errors from the loading device until the current was reset.
The present system is capable of operating efficiently with a high voltage system of much cheaper order as large fluctuations are compensated for in the novel regulator and cannot unbalance the system -- no resetting is required.
Further, previous systems of this nature embodied a high voltage source electrically connected with the data transmitting components. The high voltage source was indispensable for driving the remote device. Such condition inherently generated shock producing potentials and caused a dangerous condition to operating personnel and possible damage to the data equipment.
The herein described novel system provides complete isolation of the high voltage source from the data components, and yet maintains a high degree of current control.